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Pahlajani N , Ruth KJ , Buyyounouski MK , Chen DYT , Horwitz EM , Hanks GE , Price RA , Pollack A
RADIOTHERAPY DOSES OF 80 GY AND HIGHER ARE ASSOCIATED WITH LOWER MORTALITY IN MEN WITH GLEASON SCORE 8 TO 10 PROSTATE CANCER
International Journal of Radiation Oncology Biology Physics. 2012 Apr;82(5) :1949-1956
PMID: WOS:000301891300072    PMCID: PMC3827957   
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Abstract
Purpose: Men with Gleason score (GS) 8-10 prostate cancer (PCa) are assumed to have a high risk of micrometastatic disease at presentation. However, local failure is also a major problem. We sought to establish the importance of more aggressive local radiotherapy (RT) to >= 80 Gy. Methods and Materials: There were 226 men treated consecutively with RT +/- ADT from 1988 to 2002 for GS 8-10 PCa. Conventional, three-dimensional conformal or intensity-modulated (IM) RT was used. Radiation dose was divided into three groups: (1) <75 Gy (n = 50); (2) 75-79.9 Gy (n = 60); or (3) >= 80 Gy (n = 116). The endpoints examined included biochemical failure (BF; nadir + 2 definition), distant metastasis (DM), cause-specific mortality, and overall mortality (OM). Results: Median follow-up was 66, 71, and 58 months for Groups 1, 2, and 3. On Fine and Gray's competing risk regression analysis, significant predictors of reduced BF were RT dose >= 80 Gy (p = 0.011) and androgen deprivation therapy duration >= 24 months (p = 0.033). In a similar model of DM, only RT dose >= 80 Gy was significant (p = 0.007). On Cox regression analysis, significant predictors of reduced OM were RT dose >= 80 Gy (p = 0.035) and T category (T3/4 vs. T1, p = 0.041). Dose was not a significant determinant of cause-specific mortality. Results for RT dose were similar in a model with RT dose and ADT duration as continuous variables. Conclusion: The results indicate that RT dose escalation to >= 80 Gy is associated with lower risks of BF, DM, and OM in men with GS 8-10 PCa, independently of androgen deprivation therapy. (c) 2012 Elsevier Inc.
Notes
Pahlajani, Niraj Ruth, Karen J. Buyyounouski, Mark K. Chen, David Y. T. Horwitz, Eric M. Hanks, Gerald E. Price, Robert A. Pollack, Alan National Cancer Institute[CA-006927, CA101984-01]; Varian Medical Systems, Palo Alto, CA This publication was supported in part by Grant Nos. CA-006927 and CA101984-01 from the National Cancer Institute and by Varian Medical Systems, Palo Alto, CA. The contents are solely the responsibility of the authors and do not necessarily represent the official views of the National Cancer Institute or Varian Medical Systems. The authors appreciate the advice of Brian L. Egleston, Ph.D. 35 Elsevier science inc New york 913qa